What happens if I took money from my 401k for a home purchase and the purchase fell through

I made a hardship withdrawal of $7000 from my 401K and I had my employer take the taxes as well.  I made an offer on a home and I think I was premature on my withdrawal because the purchase fell through and now I have this money sitting in my account and I don't want to be severely penalized for not using it.  The housing market hasn't been very good, so I don't expect to find anything within 120 days. What can I do?